Fig. 2. IGF-1R is required for transactivation of insulin-stimulated EGFR. Cells were stimulated with 10 μg/ml insulin for 1 h after siRNA transfection was performed for 48 h. (A) Immunoblot analysis was performed for three TNBC cell lines (MDA-MB-436, -231, and -468) transfected with IR siRNA or scrambled siRNA control by using anti-IGF-1R, anti-p-IGF-1R (Y1280), and anti-IR antibodies. (B) siRNA-mediated suppression of IGF-1R expression in MDA-MB-436 cells expressing exogenous EGFR. Immunoblot analysis was performed using anti-p-EGFR, anti-EGFR, and anti-pIGF-1R (Y1280), and anti-IGF-1R antibodies on cells transfected with IGF-1R siRNA or scrambled siRNA control. (C) EGFR phosphorylation and internalization upon insulin stimulation were examined in cells transfected with IGF-1R siRNA or scrambled siRNA control. Scale bar, 2 ㎛. Ins, insulin.
